How to sign a document from Mail
1. Locate the attachment
Locate the email with the PDF or JPEG attachment you want to sign. Tap to download the attachment. Once downloaded, tap again to preview it.
2. Open the attachment in Genius Sign
Tap on the "Export" button at the top right of the screen.
Choose Genius Sign among the available options.
Your attachment will then open in Genius Sign and you will be ready to sign
How to sign a document from another app
Similarly to signing a document from the Mail app, open a PDF or JPEG file in the app of your choice. You then need to locate the Save as... or Export..., Open in... button (generally, it looks like a box with an arrow but it can be different depending on the app). Tap that button and choose Genius Sign in the offered options.